Field of the Invention:
The present invention relates, in general, to naturally asperated engines and, more specifically, to throttle plate position control devices for either carbureted or fuel injected engines.
In most typical internal combustion engines, the throttle plate in the carburetor or throttle body is connected by a mechanical linkage to the vehicle accelerator pedal. Any movement of the accelerator pedal is transmitted by the linkage to pivotal movement of the throttle plate to control the amount of air drawn into the engine and thereby the air/fuel mixture to control the acceleration or deceleration of the vehicle.
However, electrically operated throttle actuation are also available, and typical electric motor, throttle actuators for automotive use include conventional D.C. motors, stepper motors or brushless D.C. motors that may be attached to the throttle directly or through the use of gearing. Some of the above actuators require use of (a) more than two electric wires, a disadvantage in automotive applications, or (b) a complex (and thus less reliable) electronic control, such as the brushless D.C. motor.
An actuator embodying the present invention is directly coupled to the throttle shaft, to avoid the unreliability associated with potential gear failure, and requires only two connecting wires. Additionally, the proposed control is more size efficient than prior art limited travel actuators wherein magnetic flux passed through a toroidally wound coil wherein only that portion of the coil facing the permanent magnet rotor is magnetically active, while in the actuator embodying this invention all of the coil is active in producing torque.
While such prior art actuators have proven to be generally reliable, it is believed that further improvements can be made to control the position of the throttle plate. Specifically, the improvements contemplated by the invention are directed toward optimizing vehicle powertrain requirements, optimizing acceleration and deceleration versus fuel economy capabilities, reducing vehicle emissions and providing vehicle powertrain protection.
It is proposed that such improvements replace the mechanical linkage between the throttle plate and the accelerator pedal with an electronic control unit and a throttle plate actuator responsive to the accelerator pedal position and the position of the throttle plate itself.
Specifically, it is considered desirable to provide an apparatus for directly controlling the throttle plate position in response to accelerator pedal position without the use of a conventional mechanical linkage connected between the throttle plate and the vehicle accelerator pedal. It is also desirable to provide a throttle plate actuator which is (a) self contained and directly controls the pivotal movement of the throttle plate, (b) space efficient, (c) easily constructed, (d) provides long reliability and (e) exhibits efficient heat dissipation.